(1) Field of the Invention
The present invention relates to the manufacture of books and particularly to the joining together of book block sections by sewing. More specifically, this invention is directed to apparatus for thread-sewing book blocks which are formed from individual book block sections and especially to an improved sewing-press for bookbinding. Accordingly, the general objects of the present invention are to provide new and improved methods and apparatus of such character.
(2) Description of the Prior Art
It is known to form books, particularly books of high quality, by sewing individual book block sections together. In one prior procedure, a book block section or signature is spread open in a tent-like position. Steel needles then punch through the center fold of the section. Reciprocal hooks, which have also been thrust through the block section, catch the threads carried by the needles and thereby form loops of thread which are withdrawn from the section and linked with the loops of the next preceding block section. In this way the block sections are sewn together with a series of continuous threads which define chain stitches. The apparatus for practicing this prior technique includes a sewing head, an oscillating sewing saddle which feeds the individual block sections to the sewing head, and a delivery table for discharging the sewn sections.
The prior art apparatus, as briefly described above, has been characterized by mechanical complexity and thus relatively high cost and less than ideal reliability. This complexity has resulted from the necessity of imparting oscillatory motion to the sewing saddle, the need to impart swinging motion to feed rollers, the requirement that pressure be applied to the fold of the block sections, and the need to employ thread pushers to transfer the thread from the needles to the hooks. Additionally, the prior apparatus required moveable pre-piercing needles and relatively complex book block section holding mechanisms.